Further Physical Chemistry: Electrochemistry session 9

00:14:33
https://www.youtube.com/watch?v=V9ImmbkckhU

Sintesi

TLDRThe video examines the effect of overpotentials on electrochemical cells, focusing on the difference between measured cell potentials and thermodynamic predictions in galvanic and electrolytic cells. Overpotentials arise due to kinetic barriers, requiring higher potential to drive desired reactions. In galvanic cells, overpotential lowers the output potential, while in electrolytic cells, it increases the required voltage. The electrode material significantly affects these reactions due to varying exchange current densities, often leading to outcomes that differ from thermodynamic expectations. Understanding these effects is crucial for designing efficient electrochemical systems.

Punti di forza

  • ⚡ Overpotential is crucial for driving reactions in electrochemical cells by overcoming kinetic barriers.
  • 🔋 In galvanic cells, overpotential results in a measured potential lower than thermodynamic predictions.
  • 🔋 Electrolytic cells require higher potentials than predicted due to overpotential effects.
  • ⚙️ The performance of both types of cells depends heavily on the electrode material used.
  • 📉 Exchange current densities are key in determining which reaction predominates at an electrode.
  • 📈 Faster kinetics can lead to unexpected reactions compared to thermodynamic predictions.
  • 📊 The Butler-Volmer equation helps shape the current-voltage profile of these cells.
  • 💡 Understanding overpotentials is essential for optimizing electrochemical cell performance.
  • 🔀 Electrode design can tailor exchange current density for desired reactions.
  • 🔄 Cell reaction outcomes can vary based on applied potentials and kinetic factors.

Linea temporale

  • 00:00:00 - 00:05:00

    The video discusses overpotential in electrochemical cells, explaining it as the difference between the theoretical and actual potential at an electrode, applied via an external source. Overpotential is necessary to overcome kinetic barriers and drive current through the cell. Using the copper-silver galvanic cell, it illustrates how cell potential varies as current flows, emphasizing the role of overpotential in cell performance. By applying overpotential, we achieve different cathodic and anodic currents, shaped by the Butler-Volmer equation, essential for driving spontaneous processes to equilibrium. Holding different potentials results in no current until release, where thermodynamics causes potential adjustments to enable current flow, ultimately affecting the measurable cell potential.

  • 00:05:00 - 00:14:33

    The video transitions to electrolytic cells, where non-spontaneous reactions are driven. Applying a greater voltage than thermodynamics predict is required to drive reactions such as copper ion reduction and silver oxidation, explained through the current-voltage curve derived from Butler-Volmer kinetics. By varying applied potential, overcoming kinetic barriers is necessary for a measurable current, requiring greater overpotential than predicted by standard potential differences. Comparing galvanic and electrolytic cells, the actual measured potential varies with current: galvanic output potential is lower, while electrolytic requires higher applied voltage due to overpotential needs. The concept extends to practical scenarios like zinc and hydrogen reduction, illustrating how electrode material and kinetic considerations dominate over thermodynamic predictions, influencing industrial processes like the chlor-alkali industry. Overpotential effects crucially impact cell performance, dependent on current magnitude and kinetics, significantly shaping outcomes beyond thermodynamic expectations.

Mappa mentale

Video Domande e Risposte

  • What is overpotential in electrochemical cells?

    Overpotential is the difference between the theoretical equilibrium potential and the actual potential at an electrode. It is necessary to overcome kinetic barriers in electrochemical reactions.

  • How do galvanic cells differ from electrolytic cells in terms of overpotential?

    In galvanic cells, overpotential reduces the output potential below thermodynamic predictions, while in electrolytic cells, it increases the voltage needed to drive a current beyond thermodynamic predictions.

  • What is the role of overpotential in a galvanic cell?

    In a galvanic cell, overpotential causes the measured potential to be lower than predicted by the Nernst equation as the kinetics affect the cell output.

  • What is the impact of overpotential on the performance of electrolytic cells?

    Overpotential in electrolytic cells increases the applied voltage needed to drive the current through the cell, exceeding the predicted thermodynamic voltage.

  • How does the material of electrodes affect cell reactions?

    The electrode material affects exchange current densities and required overpotentials, which can favor certain reactions over others based on kinetic properties.

  • What example illustrates the impact of electrode material on cell reactions?

    The chlor-alkali process shows how electrode material influences reactions, where better kinetics for chlorine production dominate over expected water oxidation.

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  • 00:00:00
    we will now examine the effect of over
  • 00:00:02
    potentials in our electrochemical cells
  • 00:00:04
    in order to do this we need a first
  • 00:00:06
    quick recap of the overpotential
  • 00:00:08
    so remember we said that the over
  • 00:00:10
    potential is simply the difference
  • 00:00:11
    between the illiberal potential and the
  • 00:00:13
    actual potential at an electrode so it's
  • 00:00:15
    a fairly simple quantity to measure we
  • 00:00:18
    apply this over potential for an
  • 00:00:19
    external source so we connect
  • 00:00:21
    potentially a stat and drive this
  • 00:00:24
    potential through an electrochemical
  • 00:00:25
    cell this over potential is what we need
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    to drive a current through the cell so
  • 00:00:30
    if we simply apply the equilibrium
  • 00:00:31
    potential we're not likely to drive a
  • 00:00:33
    particularly high current we need to
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    drive a higher potential in order to
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    overcome the kinetic barriers to the
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    electrochemistry going on in our cell
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    remember that we said a lower exchange
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    current density the slower the rate at
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    which electrons are exchanged to
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    equilibrium the higher the other
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    potential we need to drive a current
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    through the cell we're going to first
  • 00:00:52
    look at galvanic cells so remember a
  • 00:00:54
    galvanic cell is one that we simply put
  • 00:00:57
    electrodes into the electrolyte and the
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    cell potential drives electrons through
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    the external circuit so let's consider
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    the cell here where we have copper and
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    silver present in the cell so this cell
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    potential we can calculate under
  • 00:01:09
    standard conditions would be about plus
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    0.4 six volts under galvanic conditions
  • 00:01:15
    we would expect to have a reduction at
  • 00:01:18
    silver electrode so we have the silver
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    ions being reduced to silver metal and
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    the copper electrode we would expect
  • 00:01:25
    have oxidation where we have the copper
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    metal going into solution as copper ions
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    but what we're really interested in with
  • 00:01:30
    the galvanic cell is as it's doing work
  • 00:01:32
    as it's driving the current through the
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    external circuit you want to know how
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    does that potential vary as the current
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    flows through the circuit and what can
  • 00:01:39
    we get from this information a key
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    factor in our galvanic cells is the
  • 00:01:44
    performance of the cell with the over
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    potential present so whenever we apply
  • 00:01:49
    an over potential to a cell remember we
  • 00:01:51
    get a different cell responds with a
  • 00:01:54
    galvanic cell the one that we were
  • 00:01:56
    looking at the copper silver cell we
  • 00:01:57
    said that we would have reduction at the
  • 00:01:59
    silver electrode so we would expect to
  • 00:02:00
    observe in this case we would expect to
  • 00:02:02
    observe a cathodic over potential so we
  • 00:02:05
    have a the cathodic current or the
  • 00:02:07
    reduction current running for a given
  • 00:02:09
    cell potential while we would have
  • 00:02:11
    oxidation at the copper electrode
  • 00:02:13
    driving an analytic current and the
  • 00:02:15
    overall current we see if you remember
  • 00:02:16
    the butler-volmer that we looked at
  • 00:02:18
    before the overall current is the sum of
  • 00:02:20
    the reduction and the the oxidation
  • 00:02:22
    currents the current voltage profile is
  • 00:02:24
    shaped fundamentally by the button of
  • 00:02:25
    Ulmer equation so the shapes of these
  • 00:02:28
    curves are exponential in nature but
  • 00:02:30
    remember this is a galvanic cell so the
  • 00:02:32
    passing of current is spontaneous it's a
  • 00:02:34
    spontaneous process as this cell strives
  • 00:02:37
    to reach equilibrium so let's now look
  • 00:02:39
    at what happens in that cell as we allow
  • 00:02:41
    that cell to pass the current if we now
  • 00:02:44
    connect a potentia stamp which allows us
  • 00:02:45
    to control the potential on the cell we
  • 00:02:48
    can hold the cell at a particular
  • 00:02:49
    potential so let's hold the cell at the
  • 00:02:51
    copper potential if we do this no
  • 00:02:54
    current flows this copper will be at
  • 00:02:56
    equilibrium no current would flow to the
  • 00:02:58
    cell however if we then release that
  • 00:03:00
    potential if we then allow current to
  • 00:03:02
    flow freely under the thermodynamics of
  • 00:03:04
    the cell the spontaneous change causes
  • 00:03:06
    the potential to increase to become more
  • 00:03:08
    positive allowing oxidation current to
  • 00:03:11
    flow at the anode and we establish an
  • 00:03:12
    equilibrium position conversely if we
  • 00:03:15
    were to change the potential and hold
  • 00:03:16
    the cell instead at the silver
  • 00:03:18
    equilibrium potential again no current
  • 00:03:21
    flows but if we've then released that
  • 00:03:23
    potential and allow the self-drive
  • 00:03:25
    current again spontaneous change will
  • 00:03:27
    cause the potential overall to decrease
  • 00:03:29
    and become less positive again allowing
  • 00:03:31
    a reduction current to flow at the
  • 00:03:32
    cathode and establishing that
  • 00:03:34
    equilibrium when we consider the
  • 00:03:37
    galvanic cell delivering energy we think
  • 00:03:39
    of it delivering a current but the it's
  • 00:03:41
    ability to deliver a current that the
  • 00:03:44
    amount of current it delivers
  • 00:03:45
    fundamentally affects the cell potential
  • 00:03:48
    because of the need to drive this over
  • 00:03:49
    potential if we think about our overall
  • 00:03:52
    cell potential we have our equilibrium
  • 00:03:54
    cell potential for copper and our
  • 00:03:57
    equilibrium cell potential for silver
  • 00:03:58
    remember these are the standard
  • 00:04:00
    electrode potentials that we can look up
  • 00:04:01
    in books and we would expect the overall
  • 00:04:03
    cell potential to be the difference of
  • 00:04:05
    these and we should be able to measure
  • 00:04:07
    this
  • 00:04:08
    however by allowing the cell to
  • 00:04:11
    equilibrate we will actually get a
  • 00:04:12
    different potential measurement from
  • 00:04:13
    that which our predictions would give us
  • 00:04:15
    as the cell runs the concentrations
  • 00:04:17
    change so we move away from ideality we
  • 00:04:20
    have an irreversible process we we might
  • 00:04:22
    lose material which causes the process
  • 00:04:24
    to be irreversible and the cell itself
  • 00:04:26
    has a fund
  • 00:04:27
    for internal resistance so in order to
  • 00:04:29
    identify how that cell potential varies
  • 00:04:31
    with current we need to find the
  • 00:04:33
    potential at two equal and opposite
  • 00:04:34
    currents so if we define two currents we
  • 00:04:38
    find that in order to drive a particular
  • 00:04:40
    positive current we need a particular
  • 00:04:42
    analytic potential and in order to drive
  • 00:04:44
    a negative current we would need a
  • 00:04:45
    particular cathodic potential what this
  • 00:04:49
    gives us over all for a given current we
  • 00:04:51
    find the difference between these new
  • 00:04:52
    potentials driving these currents and we
  • 00:04:54
    can extrapolate this to find the actual
  • 00:04:56
    measured cell potential for this current
  • 00:04:58
    as the current increases the cell
  • 00:05:01
    potential drops we only obtained the
  • 00:05:03
    thermodynamically predicted cell
  • 00:05:06
    potential under zero current conditions
  • 00:05:08
    as soon as current starts to flow we
  • 00:05:10
    start to deviate from that equilibrium
  • 00:05:12
    position what happens then with an
  • 00:05:15
    electrolytic cell where we are driving
  • 00:05:17
    the current around with this potentia
  • 00:05:18
    stat so let's consider the same cell
  • 00:05:20
    again we understand how it works under
  • 00:05:22
    galvanic conditions let's look at it now
  • 00:05:24
    under electrolytic conditions this time
  • 00:05:26
    we're going to impose a voltage to drive
  • 00:05:28
    the cell in a non spontaneous direction
  • 00:05:30
    so we're now going to drive the
  • 00:05:32
    reduction of copper instead so we now
  • 00:05:34
    bring copper two-plus to copper metal
  • 00:05:36
    and we drive oxidation at the silver
  • 00:05:39
    electrode so the opposite way around to
  • 00:05:41
    what we had with the galvanic conditions
  • 00:05:43
    now we want to think of how does the
  • 00:05:45
    current vary with the applied potential
  • 00:05:47
    and again what can we gain from this new
  • 00:05:49
    information once again we want to look
  • 00:05:52
    at the cell performance and how that
  • 00:05:53
    varies with the other potential again so
  • 00:05:55
    as we say it does still vary so let's
  • 00:05:58
    look at the current voltage curve again
  • 00:06:01
    this is a familiar shape we've already
  • 00:06:03
    seen this in terms of the butler-volmer
  • 00:06:04
    kinetics we looked at before but now
  • 00:06:07
    we're looking at a much greater
  • 00:06:07
    potential range the potential under
  • 00:06:10
    which we would expect to do real
  • 00:06:11
    electrochemistry I remember we said that
  • 00:06:14
    we'd have reduction at the copper
  • 00:06:15
    electrode so we have reduction here of
  • 00:06:18
    copper ions going to copper solid that's
  • 00:06:21
    the copper equilibrium potential no
  • 00:06:24
    current flows okay so if we're holding
  • 00:06:26
    our cell here we wouldn't expect to get
  • 00:06:28
    a current so in order to drive the
  • 00:06:30
    current through we have to drive a more
  • 00:06:33
    negative potential we have to move the
  • 00:06:34
    potential to a more negative value
  • 00:06:36
    conversely at the silver electrode if we
  • 00:06:38
    hold the cell at the silver equilibrium
  • 00:06:40
    again no current would flow we have to
  • 00:06:42
    apply an over potential to overcome the
  • 00:06:44
    electrode kinetics so that a current can
  • 00:06:46
    flow again the curves are still derived
  • 00:06:48
    from butler-volmer kinetics are still
  • 00:06:50
    fundamentally exponential remember we're
  • 00:06:53
    driving a cell against spontaneous
  • 00:06:55
    change so in this case we're forcing
  • 00:06:58
    copper to be deposited rather than
  • 00:07:00
    copper being released into solution but
  • 00:07:03
    in order to drive a cell at a particular
  • 00:07:04
    current we have to drive a different
  • 00:07:06
    potential than we predicted again
  • 00:07:08
    remember the difference between these
  • 00:07:10
    standard potentials would be expected to
  • 00:07:12
    give us our cell potential but in order
  • 00:07:15
    to get a measurable current we have to
  • 00:07:17
    apply a much greater over potential so
  • 00:07:19
    we apply the same principles as for the
  • 00:07:20
    galvanic cell we identify current
  • 00:07:22
    required so we identify our anodic and
  • 00:07:24
    cathodic components and the applied
  • 00:07:27
    voltage that we need is once again the
  • 00:07:29
    same separation from the tie lines as we
  • 00:07:31
    found before meaning that we have to
  • 00:07:33
    apply a much greater potential in order
  • 00:07:35
    to drive a current through that cell
  • 00:07:36
    than thermodynamics would otherwise
  • 00:07:38
    predict when we compare the galvanic and
  • 00:07:41
    electrolytic cells we can always use
  • 00:07:43
    thermodynamics to predict the cell
  • 00:07:44
    potential however when we actually come
  • 00:07:47
    to do measurements we find that the
  • 00:07:48
    output potential of a galvanic cell is
  • 00:07:50
    considerably lower than that predicted
  • 00:07:52
    by thermodynamics while the charging
  • 00:07:55
    potential of an electrolytic cell is
  • 00:07:56
    considerably greater than that predicted
  • 00:07:58
    by thermodynamics no matter which cell
  • 00:08:00
    we're looking at the measured potential
  • 00:08:02
    varies with current so depending on what
  • 00:08:05
    current is being driven through the cell
  • 00:08:06
    or the cell is supplying we would expect
  • 00:08:08
    to measure a different potential coming
  • 00:08:10
    out of that cell so for a galvanic cell
  • 00:08:12
    the effect of the over potential is to
  • 00:08:15
    reduce the output of the cell from that
  • 00:08:17
    predicted by the Nernst equation whereas
  • 00:08:19
    with electrolytic cells the effect of
  • 00:08:20
    our potentials is to increase the
  • 00:08:22
    applied voltage required to put a
  • 00:08:24
    current through the cell we always have
  • 00:08:26
    a struggle between kinetics and
  • 00:08:28
    thermodynamics thermodynamics predicts
  • 00:08:30
    overall outcomes for our reactions for
  • 00:08:32
    our cell potentials for everything in
  • 00:08:33
    chemistry while kinetics says how fast
  • 00:08:36
    something happens so if we consider a
  • 00:08:39
    particular cell where we've dissolved
  • 00:08:41
    ink chloride in a solution at 10 to
  • 00:08:44
    minus 2 molar and we maintain the pH at
  • 00:08:48
    7 we would expect to see these cell
  • 00:08:50
    potentials when we look at this couple
  • 00:08:52
    we can see that we have two
  • 00:08:54
    possible reductions happening we can
  • 00:08:56
    either reduce H+ to hydrogen gas or we
  • 00:08:58
    can reduce zinc two plus two zinc methyl
  • 00:09:01
    so more than one outcome can come out of
  • 00:09:03
    this cell so are we going to reduce zinc
  • 00:09:06
    or are we going to reduce hydrogen if we
  • 00:09:08
    look at the current voltage curves again
  • 00:09:11
    and we think about sweeping our voltage
  • 00:09:14
    to negative potential so we start our
  • 00:09:15
    voltage at zero and we drive it to
  • 00:09:18
    negative voltages we would expect to see
  • 00:09:21
    hydrogen evolution happening once we get
  • 00:09:24
    to a potential of minus 0.41 4 volts so
  • 00:09:29
    as we come into this region here we
  • 00:09:32
    start to apply the over potential and we
  • 00:09:33
    would expect start seeing hydrogen
  • 00:09:34
    evolution while we would expect to see
  • 00:09:36
    zinc if we drive it further past the
  • 00:09:39
    zinc electrode potential but the result
  • 00:09:42
    that we observe depends fundamentally on
  • 00:09:44
    the electrode material we're using so
  • 00:09:46
    depending on the value of the over
  • 00:09:47
    potential required to deliver a
  • 00:09:49
    particular current we may see a
  • 00:09:51
    different result so let's look at what
  • 00:09:52
    happens once we start varying the
  • 00:09:53
    electrode potential let's consider
  • 00:09:55
    platinum and mercury electrodes if we
  • 00:09:58
    look at the exchange current densities
  • 00:09:59
    for each one for the hydrogen couple and
  • 00:10:01
    for the zinc couple we can see there's a
  • 00:10:03
    big difference between the exchange
  • 00:10:04
    current potentials for hydrogen whether
  • 00:10:06
    we're at the mercury or the Platinum
  • 00:10:08
    electrode while for zinc it's largely
  • 00:10:10
    unchanged it's still a very high
  • 00:10:11
    exchange current density so let's
  • 00:10:13
    consider platinum first let's look at
  • 00:10:15
    platinum where hydrogen has a rip
  • 00:10:16
    moderately high exchange current density
  • 00:10:18
    so zinc reaction has fast kinetics it
  • 00:10:21
    has the high exchange current density we
  • 00:10:23
    expect to see fast kinetics going on so
  • 00:10:25
    we would see high reduction currents
  • 00:10:27
    near the zinc equilibrium potential the
  • 00:10:29
    hydrogen is also fast it's also
  • 00:10:31
    relatively fast we might need a slightly
  • 00:10:33
    higher over potential required but we
  • 00:10:34
    can still drive a current through the
  • 00:10:36
    cell and see hydrogen production so as
  • 00:10:38
    we sweep our potential from zero down
  • 00:10:40
    through the hydrogen potential we start
  • 00:10:44
    to see hydrogen production at the
  • 00:10:46
    expected voltage this is an expected
  • 00:10:48
    result and something that shouldn't
  • 00:10:49
    worry us too much
  • 00:10:50
    let's however now consider mercury
  • 00:10:53
    electrodes the equilibrium values are
  • 00:10:57
    unchanged but we've now gone into a
  • 00:10:59
    situation where hydrogen has very poor
  • 00:11:01
    kinetics it's got a very very small
  • 00:11:03
    we've got nine orders of magnitude
  • 00:11:05
    difference in the
  • 00:11:06
    James current density so very per
  • 00:11:08
    kinetics for hydrogen what that means is
  • 00:11:10
    we require a very large overpotential to
  • 00:11:13
    drive a current and what that means the
  • 00:11:15
    over potential we have to apply is
  • 00:11:16
    considerably greater than that for the
  • 00:11:18
    zinc couple the overall result of this
  • 00:11:22
    is that because the zinc still has fast
  • 00:11:23
    kinetics and only requires a small
  • 00:11:25
    overpotential predominately at the
  • 00:11:27
    mercury electrode we would expect to see
  • 00:11:29
    the zinc reaction first the effect of
  • 00:11:32
    these electrode kinetics can't be
  • 00:11:34
    ignored so depending on how we design
  • 00:11:36
    our electrodes I would design the
  • 00:11:37
    material that we're working with we can
  • 00:11:39
    tailor our exchange current density to
  • 00:11:42
    get different results of the electrode
  • 00:11:45
    an example of this is a chlor-alkali
  • 00:11:47
    industry where we electrolyze sodium
  • 00:11:50
    chloride solution or salt water I'm not
  • 00:11:53
    going to go into too much detail about
  • 00:11:54
    it because it's a standard a-level case
  • 00:11:56
    study but fundamentally we have two
  • 00:11:58
    electrodes our cathode and our anode
  • 00:12:00
    each which has a competing process the
  • 00:12:02
    cathode processes center around the
  • 00:12:04
    reduction of sodium to sodium metal or
  • 00:12:06
    the reduction of water to hydrogen and
  • 00:12:08
    hydroxide when we look at this we see
  • 00:12:11
    that we have a huge thermodynamic
  • 00:12:13
    barrier to overcome to reduce sodium
  • 00:12:15
    while a barrier is not quite so great
  • 00:12:16
    for the reduction of water however if we
  • 00:12:18
    look at the anode processes the
  • 00:12:20
    electrode potentials are very similar so
  • 00:12:22
    we now need to think about the kinetics
  • 00:12:24
    of what's going on looking at the third
  • 00:12:26
    dynamics we would expect to see a lower
  • 00:12:29
    barrier for the oxidation of water to
  • 00:12:31
    hydrogen oxygen than we would for the
  • 00:12:34
    oxidation of chloride to chlorine gas
  • 00:12:36
    but when we look at the exchange current
  • 00:12:39
    densities at the electrode we see that
  • 00:12:40
    the kinetics for the chloride oxidation
  • 00:12:43
    are considerably better we have a much
  • 00:12:45
    greater exchange current density than we
  • 00:12:47
    have for the water at that electrode so
  • 00:12:51
    thermodynamics predicts that we should
  • 00:12:52
    get hydrogen gas and oxygen gas as
  • 00:12:54
    products from this reaction because we
  • 00:12:57
    have a lower electrode potential for
  • 00:12:59
    each one so the thermodynamics predicted
  • 00:13:01
    however when we look at the exchange
  • 00:13:04
    current density as a function of the
  • 00:13:06
    applied potential we see that the
  • 00:13:09
    exchange current to that part on time
  • 00:13:11
    electrode affect the outcome of the
  • 00:13:13
    reaction because of the much much
  • 00:13:15
    smaller exchange current density we
  • 00:13:16
    require a very high over potential for
  • 00:13:19
    the oxygen water
  • 00:13:19
    couple and we see that we need to apply
  • 00:13:21
    very very high over potential to supply
  • 00:13:23
    any measurable amount of currents to
  • 00:13:25
    actually make that reaction proceed if
  • 00:13:27
    we look at chlorine instead we find that
  • 00:13:30
    for the same potential we get a much
  • 00:13:32
    greater current happening with the
  • 00:13:33
    chlorine so the chlorine production
  • 00:13:35
    dominates to summarize we need to
  • 00:13:39
    remember that electro process is
  • 00:13:40
    fundamentally effect thermodynamic
  • 00:13:42
    predictions in a galvanic cell we see
  • 00:13:44
    that the actual cell potential is
  • 00:13:46
    considerably lower than we would
  • 00:13:47
    otherwise expect while for an
  • 00:13:49
    electrolytic cell the cell potential is
  • 00:13:52
    higher than we would expect because of
  • 00:13:54
    the over potentials required to drive a
  • 00:13:55
    current through the cell the value of
  • 00:13:59
    that cell potential fundamentally
  • 00:14:00
    depends on the magnitude of the current
  • 00:14:02
    so if we have a high current we would
  • 00:14:04
    expect to see a lower galvanic cell
  • 00:14:06
    potential whereas if we drive a high
  • 00:14:08
    current through an electrolytic cell
  • 00:14:10
    you'd expect to see a higher selves of
  • 00:14:11
    potential required the effect of faster
  • 00:14:14
    kinetics also can't be ignored faster
  • 00:14:16
    kinetics can favour adverse
  • 00:14:17
    thermodynamics if it forms faster we
  • 00:14:20
    will get more of a happening through
  • 00:14:22
    modification of our electrodes we can
  • 00:14:23
    increase the exchange current density
  • 00:14:25
    which will favour particular processes
  • 00:14:27
    to our advantage
Tag
  • overpotential
  • electrochemical cells
  • galvanic cell
  • electrolytic cell
  • kinetics
  • thermodynamics
  • cell potential
  • exchange current density
  • Butler-Volmer equation
  • electrode material